as we all know, all toy radio controlled cars, (and other new pressies), run out of main motor drive power long before the radio kit does....

so how about fitting a CLOCKWORK main motor?

a basic one could be, a simple drive system, with only forward and reverse,
this inturn could drive a simple skid steer system.
or who remembers the old 'Sonic controlled cars' where the reverse gave us a turning action...

if the car radio battery was a permenantly installed nicad, this could be charged by the wind up transmitter's own generator circuit, giveing total freedom from the mains,(given that it may take a while to charge both batts simultaneously).maybe this one will still be running on boxing day... Mandy

You can get flashlights and radios that are recharged by cranking a crank which stores potential energy in a spring. This is then doled out through a generator. See link for details. Of course it takes lots more energy to run a car around than it does to operate a flashlight, so maybe this wouldn't be too practical.